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Discussion Starter · #1 ·
I bought a parts mower recently and the transmissions were said to be slipping on an incline, can they be rebuilt? i ask being its an opportunity to have spares. The mower in question is an 05 RZT50 cub.
 

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You need to figure out which specific hydro's (as they typically use an all-in-one unit combining hydraulic pump, controller, and motor). Examine the outside of both hydrao's for a label/markings/stickers to indicate the maker and model/serial number of them. You can likely get spare parts, and at least some of the manufacturers have service/repair manuals available for free. IMHO, if you have the time/inclination/some special tools (a press/pullers/measuring tools), it can be cost effective to rebuild them, but if you have to pay someone else to do it, the cost rapidly heads towards (or can exceed) the cost of a replacement unit.
 

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ever change the oil in the HYDRO DRIVE??? they are supposed to have oil changed every <200 hours and new filter if so equipped.. .with SPECIAL HYDRO FILTER e bay $8. the factory i read on other post fills them with 10-40 motor oil??? can get special HYDRO 15-50 synthetic oil at the farm supply store or Mobil 1 in 15-50 variety... but if the unit is questionable ... put $10 gal WM motor oil in it and see what that does. someone put 80-90 gear oil in their said that it quit whining? 90 wt gear oil is 50 wt. i wud change it twice... with $10 gal 10-40 WM diesel oil... see how that works... then go to something heavier if that doesnt work out too well.

if the HYDRO unit is WORN from lack of oil changes... it is worn. the tolerances for the 5 shooter revolver piston/cyl is like .001" and when they get to .003" they are WORN and bleed fluid past the piston/cyl and not too good at going uphill . mine does that when COLD... without letting the HYDRO unit warm up for 5 mins before the first run of the day when it is "cold" (30 at night). the unit was/is WORN from lack of maint i resurrected it when the prvious owner said "it wont go fwd?" one of the check valves in the pump cavity had fallen into the pump cavity... from kids horsing it.. ramming it from FWD to REV when they didnt know how to slow it down with throttle/clutch?

the impression i got when HYDROs are WORN from lack of FRESH OIL every 2 years or 100 hours... might end up putting gear oil in them to get the last out of the hydro unit or open it up to replace the 5 shooter revolver piston/cyl... if can get them for your model. why they dont write on the back of unit CHANGE THE OIL IN THE TRANSAXLE EVERY 2 years or 100 hours for long happy HYDRO DRIVE LIFE. USE 15-50 MOBIL 1 Synthetic oil... 66-122 oz.. drains when take filter off... fill thru vent hose til full, start/idle wheels off ground.

I took fender/seat off since i had to take my HYDRO OUT to get to the pump/check valves and clean off the grass "blanket" on the HYDRO.. that runs HOT enuf and does not need a grass blanket on it to keep it warm... 180* in 5 mins with wheeels off the ground, no load on 75* day is pretty warm/pretty quick. that is why use synthetic oil that doesnt cook so fast like dino oil does at HIGH TEMPERATURES of HYDRO UNITS) add more oil, let it burp, add more oil, in fwd/rev at idle... pull/push in the thing taht allows the tractor to be pushed by hand (on the back of unit) to burp that part of the system... still in gear, but wheels wont turn as it flows thru the override on the HYDRO unit. abt 10 or so mins of idling.. fast idle in gear and wont be able to get any more oil in the vent as it is full. go for test spin...

i dont think HYDRO drives are really made to be dozers or TRACTORS,,, just mow the lawn. maybe blow snow/push a little snow. ppl use them or TRY to use them as TRACTORS and pull a plow... why they have plow stuff for them? it has to cook the HYDRO fluid fast. they did that with WW 2 army jeeps, sold implements for them to pull... a plow.

4x4 mag tested the Willys with a plow attachment on it... after one ditch dug... they could spell the burning gear oil in the differentials/xfer case/transmission as the plow was just too much for the little 1/4 ton jeep. it did it.. it just DID NOT LIKE IT. same with HYDRO drives.. treat them well/change oil/filter and dont try to move loaded car trailers with them and they will last long time... misuse them... and .. the HYDRO DRIVE unit is shot.. tractor is shot

[Moderator note... we don't need fancy fonts and colors, thanks.]
 

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Discussion Starter · #4 ·
Thanx guys, i'll start doing my homework.
 

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'81 Gravely tractor, 50's 60's 70's 80's 90's Gravely tractors Various Honda Power equipment
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The RZT50's used a light duty Hydro-Gear unit, all in one, pump, motor, transmission without an external oil filter.
You have to split open the case to change the oil filter after you dis-assemble the transmission. If you just want to change the oil in them you have to remove the trans unit from the tractor and turn them upside down to dump out the oil, then refill them and re-install them on the tractor.
The RZT50's are a 'Light Duty' 'Homeowner' model Zero-Turn mower.
You could use a 20w50 synthetic oil in them to help it with the slowing down for a little while, or use 80-90 gear oil, but that will only last for a little while, maybe a season or two, then you would be looking at an overhaul like new pistons and cylinder blocks plus a few other parts, and they are expensive, you would be getting up close to the cost of a new trans unit before you are done with it.
They normally use a 5W30 synthetic oil in them from new.
 
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